Five-Power Naval Limitation Treaty

The leading post-World War I naval powers of Britain, France, Italy, Japan and the United States concluded a landmark agreement that was intended to slow the burdensome arms race and, it was hoped, reduce the possibilities for future wars.

All signatories pledged to maintain a balance in their respective capital* fleets under a predetermined ratio:

Britain

5

United States

5

Japan

3

France

1.67

Italy

1.67

All signatories agreed to honor a naval construction "holiday" for a period of 10 years.

The major Pacific naval powers  Britain Japan and the United States  with some specific exceptions, agreed not to increase fortifications on their Pacific bases. This provision was included to help Japan overcome its reluctance to accept a smaller naval role.

The results of this treaty were significant. In an almost unprecedented action, major powers voluntarily reduced their navies. The United States scrapped or halted current construction on 26 ships, the British 24 and the Japanese 16.

The Five-Power Pact continued to be observed into the 1930s, but then an increasingly militant Japan demanded parity with the U.S. and Britain. That request was denied and Japan in 1934 gave notice that it would withdraw from the treaty in two years  and did so.

*Capital ships were those vessels exceeding 10,000 tons or bearing guns in excess of an eight-inch caliber, effectively denoting battleships and aircraft carriers.

See also a discussion of the general results of the Washington Conference.